KYIV, Ukraine – Ukrainian authorities on Sunday accused Russian forces of bombing a school in the besieged city of Mariupol where some 400 people, including women and children had been sheltering, and of deporting some residents to Russia.

Mariupol has been one of the main targets of Moscow's attacks. Russian shelling has hammered the eastern Ukrainian port for days, and the city has seen a near total communication blackout.

"Yesterday, the Russian occupiers dropped bombs on an art school No 12," the city council said on messaging app Telegram on Sunday, adding that around 400 women, children and elderly people had been sheltering there from bombardments.

The building, which is located in the east of the city, had been destroyed, the council said in a statement. "Peaceful civilians are still under the rubble," it added.

City authorities also claimed that some residents of Mariupol were being forcibly taken to Russia and stripped of their Ukrainian passports.

"People who are being forcibly taken to Russia are being stripped of their Ukrainian passports and given a piece of paper that carries no legal weight and is not recognised by the entire civilised world," the city council said.

Pavlo Kyrylenko, head of the Donetsk regional administration, said that Russian forces had already deported more than a thousand residents of Mariupol.

"The occupiers are sending the residents of Mariupol to filtration camps, checking their phones and seizing (their) Ukrainian documents," he added, urging the international community to intervene.

"I appeal to the international community: put pressure on Russia and its madman of a leader," he said on Facebook.

Separately, Petro Andryushchenko, an adviser to Mariupol's mayor, said that the residents of the besieged city were taken to the Russian cities of Tomsk, Vladimir and Yaroslavl.